From a record high in 2015 of 4,279, US expats giving up citizenship and returning their passports surged to 5,411 in 2016, setting a new record.

The figures issued by the US Treasury Department show annual increases for the past four years and are thought to be tied to increased activity by the Internal Revenue Service’s hunt for undeclared assets belonging to US expatriates. Enforcement of the controversial Foreign Account Tax Compliance Act (FATCA) rules has also caused difficulties for many Americans living overseas as regards retaining US bank accounts as well as opening new accounts in their countries of residence.

Since the shock result of the presidential election last November, social media sites have seen a huge increase in the number of US nationals posting their intention to give up their citizenship. It’s not just those holding American passports who are deciding to cut their ties with the home country, as the Treasury Department’s figures also include a number of long-term resident green card holders who’ve given up on the complicated annual tax paperwork now required.

One surprise in the Treasury's long list of names is Britain’s Foreign Secretary Boris Johnson, who held dual citizenship due to the fact he was born in the USA to British parents, although he only lived there for five years before the family returned to the UK.

The previous Mayor of London and formerly a journalist, Johnson became less than overjoyed with the American tax system when the IRS billed him for an amount supposedly based on capital gains tax on the sale of his London home. On receiving the surprise bill, Johnson described the amount demanded as ‘absolutely outrageous’ and at first refused to pay, stating the American tax authority was ‘coming after him’. Eventually, he paid.

Since the issue, he’s been outspoken on several fronts, suggesting he’d prefer not to visit New York as he might meet the newly sworn-in President Trump, and has been less than polite about Hillary Clinton. The Treasury document lists him as Boris Alexander Johnson, possible not realising his full name is Alexander Boris de Pfeffel Johnson.